[Study] Longer Sprint Intervals Boost Muscle Oxygen Utilization

Physical activities like jogging, walking, cycling, and sprinting engage the musculoskeletal system and utilize energy. Sprint interval training (SIT) involves cycles of intense exercise followed by short rest periods. The structure of these cycles can significantly impact physiological responses.

Recently, researchers have focused on optimizing SIT protocols to enhance athletic performance and overall well-being.

A recent study by Japanese researchers, Dr. Takaki Yamagishi from the Japan Institute of Sports Sciences and Waseda University, and Professor Yasuo Kawakami from Waseda University's Human Performance Lab, examined the benefits of SIT.

Published in Medicine & Science in Sports & Exercise on March 7, 2024, the study investigated how different sprint interval exercises (SIE) affect muscle oxygen utilization and metabolic responses.

The researchers compared two SIE protocols: SIE20, with two 20-second sprints and 160-second recoveries, and SIE10, with four 10-second sprints and 80-second recoveries.

They measured pulmonary oxygen uptake (V̇O2) and tissue oxygenation index (∆TOI) in thigh muscles, using T2-weighted MRI to assess muscle activation.

Results showed that SIE20 outperformed SIE10 in enhancing whole-body and peripheral oxidative metabolism. While both protocols increased V̇O2 levels, ∆TOI, and MRI T2 values, SIE20 led to greater peripheral oxidative metabolism. Successive sprints in SIE10 did not correlate with increased oxidative metabolism.

Dr. Yamagishi emphasized the practical benefits:

“Our study’s exercise modalities require less than 15 minutes to complete and provide significant health benefits.”

These findings address gaps in SIT research, highlighting the effects of sprint duration and repetitions on aerobic and metabolic responses.

Future studies could further refine exercise guidelines and establish the dose-response relationship between exercise volume, intensity, and training adaptations, potentially influencing recommendations by organizations like the American College of Sports Medicine.